///2009 Abstract Details
2009 Abstract Details2019-08-03T15:55:31-06:00

Low-Dose Bupivacaine Compromises the Efficacy of Spinal Anesthesia for Cesarean Delivery: Systematic Review and Meta-Analysis

Abstract Number: 55
Abstract Type: Meta Analysis/Review of the Literature

Cristian Arzola MD, MSc1 ; Paul M. Wieczorek MD2

Introduction: Cesarean delivery is the most common surgical procedure in the United States. Spinal anesthesia is the preferred anesthetic technique for elective cesarean deliveries. Unfortunately, hypotension is the most common side effect with both maternal and neonatal consequences. Multiple strategies have been attempted to prevent spinal-induced hypotension, including the use of low-dose bupivacaine. Narrative reviews have addressed the controversial issue of reducing the dose of bupivacaine, highlighting a possible compromise of the anesthetic efficacy (1,2). This systematic review examined the anesthetic efficacy of low dose versus conventional dose bupivacaine in elective cesarean delivery. Methods: We searched CENTRAL, Medline, Embase and LILACS for RCTs comparing spinal bupivacaine in low doses (LD ≤8mg) with conventional doses (CD >8mg).The two authors independently assessed trial eligibility, methodological quality and data extraction. Our primary outcomes were need for analgesic supplementation and conversion to general anesthesia during the procedure. Secondary outcomes included:maternal side effects (hypotension, nausea-vomiting), neonatal outcomes (Apgar score, acid-base status) and clinical quality variables (patient satisfaction, surgical conditions). Results: We retrieved 29 trials for eligibility assessment, 9 were included in the data extraction and 8 were used in the meta-analysis for the primary outcome (505 participants). In the LD group, the need for analgesic supplementation was significantly higher (RR 3.81 [95%CI 2.28-6.36], NNT 5 [95%CI 3-11], fig1). Furthermore, the LD group exhibited a lower risk of hypotension (RR 0.75 [95%CI 0.58-0.97]) and nausea-vomiting (RR 0.65 [95%CI 0.45-0.95]). Conversion to general anesthesia was not statistically estimable. We investigated sources of heterogeneity, subgroup analyses and meta-regression for confounding variables (baricity, intrathecal opioids, lateral vs sitting position and uterine exteriorization). Sensitivity analysis was performed to test the robustness of the results. Discussion: This meta-analysis demonstrates that low-dose bupivacaine spinal anesthesia compromises the anesthetic efficacy (risk of analgesic supplementation: high grade of evidence), despite the benefit of lower maternal side effects (hypotension, nausea-vomiting: moderate grade of evidence). References:(1)Curr Opin Anaesthesiol 2004,17:301-308 (2)Curr Opin Anaesthesiol 2008,21:259-262

SOAP 2009